Histopathology of the conduction system in the sudden infant death syndrome.

The cause of the sudden infant death syndrome (SIDS, crib death, or cot death) is unknown. Current hypotheses include lability of heart rate and/or rhythm as a pathogenetic factor. The conduction system of 50 infants coming to autopsy were examined by serial sections; the infants were from newborn to two years of age. Twenty-six were SIDS deaths and 24 were explained deaths (ED). The frequency of histologic abnormalities of the specialized tissue was almost identical in both groups of infants. Hemorrhage in or around different parts of the conduction system was present in 27% SIDS and 29% ED. There was no evidence of cell death or degeneration of conduction fibers, nor obstructive lesions of the atrioventricular (A-V) arteries. Apparent moulding of A-V node and His bundle was a universal finding in both SIDS and ED, and consisted of irregular interdigitation of A-V node and His bundle fibers with the myxoid central fibrous body (CFB). Isolated bundles of conduction fibers residing in CFB and membranous ventricular septum were seen in two SIDS, but no direct contact between these fibers and the working myocardium could be identified in serial sections in either case. Without corroborating antemortem electrophysiologic data, the functional significance of morphologic findings in the conduction system of SIDS must remain conjectural.     

Provider Visits and Early Vascular Access Placement in Maintenance Hemodialysis

Medicare reimbursement policy encourages frequent provider visits for patients with ESRD undergoing hemodialysis. We hypothesize that patients seen more frequently by their nephrologist or advanced practitioner within the first 90 days of hemodialysis are more likely to undergo surgery to create an arteriovenous (AV) fistula or place an AV graft. We selected 35,959 patients aged ≥67 years starting hemodialysis in the United States from a national registry. We used multivariable regression to evaluate the associations between mean visit frequency and AV fistula creation or graft placement in the first 90 days of hemodialysis. We conducted an instrumental variable analysis to test the sensitivity of our findings to potential bias from unobserved characteristics. One additional visit per month in the first 90 days of hemodialysis was associated with a 21% increase in the odds of AV fistula creation or graft placement during that period (95% confidence interval, 19% to 24%), corresponding to an average 4.5% increase in absolute probability. An instrumental variable analysis demonstrated similar findings. Excluding visits in months when patients were hospitalized, one additional visit per month was associated with a 10% increase in odds of vascular access surgery (95% confidence interval, 8% to 13%). In conclusion, patients seen more frequently by care providers in the first 90 days of hemodialysis undergo earlier AV fistula creation or graft placement. Payment policies that encourage more frequent visits to patients at key clinical time points may yield more favorable health outcomes than policies that operate irrespective of patients’ health status.     

The Association between Asthma and Absenteeism among Working Adults in the United States: Results from the 2008 Medical Expenditure Panel Survey

Objective. The purpose of this study was to evaluate the association between asthma status and the occurrence and length of work absences among the US working adults. Methods. A cross-sectional study was conducted using the 2008 Medical Expenditure Panel Survey (MEPS). Employed respondents between ages 18 and 55 years were included. The association between asthma status (whether respondents have asthma or not) and occurrence of absences and the length of time per absence was evaluated using a two-part model. A multivariate logistic regression as the first part of the model was to estimate the probability of being absent from work at least once during the observation period as a function of asthma status. A multivariate negative binomial regression as the second part of the model was used to assess whether the length of each absence from work was associated with asthma status among respondents who reported at least one absence from work. Sociodemographic, socioeconomic, employment-related, health status, and comorbidity variables were included in each model as covariates. Results. Of 12,161 respondents, 8.2% reported having asthma, which accounted for 10.4 million working adults in the United States in 2008. Employed adults with asthma were more likely to report having at least one absence from work compared to those without asthma in bivariate analyses (26.2% vs. 16.2%, p?相似文献   

There's more to flow-mediated dilation than nitric oxide

Flow-mediated dilation (FMD) is the standard tool used to assess endothelial function. The premise behind the standard FMD test is that it serves as an endothelial-dependant nitric oxide bioassay; however, the endothelium may release additional dilatory molecules which contribute to FMD, most notably prostacyclin and endothelial-derived hyperpolarizing factor. The relative importance of these molecules to the dilatory response may vary substantially among individuals, particularly in response to a number of diseased states. This review discusses how each of these molecules may contribute to vasodilation, and considers the circumstances in which they may vary.     

Sleep Apnea: Is Routine Preoperative Screening Necessary?

Background

Because perioperative complications of unrecognized obstructive sleep apnea (OSA) can be severe, many bariatric surgery programs routinely screen all patients. However, many obese non-bariatric surgery patients do not get screened. We wanted to evaluate the need for routine preoperative OSA screening.

Methods

Morbidly obese patients with a body mass index (BMI)?>?40 kg/m² undergoing bariatric surgery—all screened for OSA—were compared to morbidly obese orthopedic lower extremity total joint replacements (TJR) patients—not screened for OSA. Cardio-pulmonary complications were recorded.

Results

Eight hundred eighty-two morbidly obese patients undergoing either bariatric (n?=?467) or orthopedic TJR surgery (n?=?415) were compared. As a result of screening, 119 bariatric surgery patients (25.5 %) were newly diagnosed with OSA, bringing the incidence to 42.8 % (200/467). Orthopedic surgery group had 72 of 415 (17.3 %) patients with pre-existing OSA. The unscreened orthopedic patients had a 6.7 % (23/343) cardiopulmonary complications rate compared to 2.6 % (7/267) for screened bariatric surgery patients. This difference was not statistically significant when adjusted for age and comorbidity (p?=?0.3383).

Conclusion

Sleep apnea screening prior to bariatric surgery identifies an additional 25 % of patients as having OSA. In this study, unscreened morbidly obese patients did not have an increased incidence of cardiopulmonary complications after surgery compared to screened patients. Prospective randomized studies should be conducted to definitively assess utility and cost effectiveness of routine OSA screening of all morbidly obese patients undergoing surgery. Preoperative OSA screening may be safely omitted when randomizing patients for such a trial.